Electrical apparatus.



L. BLISS.

ELECTRICAL APPARATUS. APPLICATION FILED NOV. 1,1906.

1,022,058. Patented Apr. 2, 1912.

awve/wkm UNITED STATES PA ENT OFFICE.

WILLIAM Loan BLISS, or BROOKLY QNEW YORK.

Q ELECTRICAL APPARATUS. I

Specification of Letters Patent.

Application filed November 1, 1906. Serial Np. 341,534.

commonly'known as multiple filament or turn-down lamps.

In multiple filament lamps the luminosity is controlled by circuit conditions. The lamp of my invention is adapted to either alternating or direct current circuits, andit is possible to control a'plu'rality by the same instrumentality and from a distantpoint, if desired. v

Figure 1 isa' diagrammatic view of a systom and apparatus embodying my invention, Fig. 2 is a side View of a lamp and vertical sectional view and side elevation of a socket and lamp with conductors embodying my invention, Fig. 3 is a detail view, showing one form of switch for use in thesystem, the connections being such as to cause'the maximum luminosity of the lamp or lamps in circuit. Fig. 4. is a similar view, the circuit being open so that the lamp or lamps will be out. Fig. 5 is a similar view, but showing the connections such that the lamp or lamps will be giving -minimum' luminosity;

1 indicates the lamp bulb containing the high resistance filament 2 and the low resistance filament'3. This bulb has a suitable insulating base. One end of the filament 3 is connected to the externally screw-thread-- ed metallic annular terminal 4. One end of the filament 2 is connected to the central metallic disk terminal 5. Both filaments are also connected to the intermediate metallic annular terminal 6. The bulb 1 together 4 terminal 7 and spring arm terminals 8 and 9 tomary in socket construction. The conductor for the socket is composed of the three insulated wire members 0, 2' and c, which are preferably braided together and connected respectively to the threaded terminal 7 and Pat-entedApr. 2, 1912.

the spring terminals 8 and 9. .It will thus be seen that when the lamp is in the socket, the wires 0,2 and 0 are connected respectively to the outer terminal 4 for the low resistance filament 3, the inner terminal 5 of the high resistance filament 2, and the intermediate terminal 6 common to both filaments; The circuit from wire 0 to the outerterminal '7 passes through the frame 11 and switch member 12, so that the circuit may be opened and closed in the socket. s

X'and Y indicate the malns of a generating circuit.

The three distributing wires. 0, 'i and a may be connected to one or more lamps, as

shown in the diagram of Fig. 1. The connections between the generating and dis'tributing circuits is under the control of a suitable device. Fig. 1 shows the controller in its simplest form, in which it consists of the movable switch arm 16 connected to main X,and two stationary contacts 17 and 18 connected to the branch distributing wires 2' and 0 respectively. The main Y is connected direct to the distributing branch 0..

In the position of the controller shown in Fig. l, current'will pass from the main X through switch arm 16, contact 17, distributing branch 1', thence to the inner ter minal and high resistance filament of each lamp in circuit, thence 'to the low resistance filament of each lamp in circuit, and back through the outer terminal of each lamp and through the distributing branch 0 to the main Y. This position may be called the series position for both filaments in each lamp, and is indicated by the arrow S. When the filaments are in series, the poten tial drop in each is proportional to its res'istance.v The resistance of the filaments is designed so that under the voltage available in the-system thehigh resistance filament in the series arrangement will receive sufiicient current to heat it to incandescence. Under these conditions the proportion of current available for the low resistance fil amentjis insufiicient to heat it to incandescence, the lamp is accordingly lighted,

turned down or dim. When the but c parallel, so that in effect the high resistance rotation step by'step, one-eighth of a turn ,for

is particularly each change. This Such a switch adapted for snap switches.

, would have t-h e main contacts 19 and 20 for the generating circuit wires Y and X respectively, and the contacts 21, 22 and 23 for the distributing wires 2', c and 0 respectively The switch arms 24 and 25 are insulated from each other but mounted to rotate'together' similar to the old style of switch arms in snap switch practice. When the parts are in the position shown in Fig. 3, the lamp or lamps in the distributing circuit will be turned on bright, the lower resistance filaments being incandescent, since the high resistance filament or filaments are short-circuited hy a part of the switchfarm 25. An eighth of a turn in a clockwise direction brings the parts into the positionshown in Fig. 4, when the circuits are open and the lamp or lamps out. Another eighth of a turn'from the position shown in Fig. 4 and in a clockwise direction will bring the parts to the position shown in Fig. 5, in

which the high and low resistance filaments of the lamp or lamps are in series, andthe high resistance filament incandescent and consequently on dim. Another eighth of a turn in a clockwise direction from the position shown in Fig. 5, will throw the arm 24 off the contacts 20 and 21 and open the circuit to turn ofl the lamp or lamps.

-whether the multiple filament lamp is to be bright or dim is, however, determined by the controller andthe circuit connections, which are otherwise supposed to be permanent. In the form in which the circuits are illustrated, a single filament lamp in one of my sockets will be turned on when the controller is in either the position shown in Fig. 3 or in Fig. 5.

Ordinary single filament lamps, such as 26 and 27 may be connected in the same circuits with the multiple filament lamps between the conductor 0 and either conductor 2' or 0, depending upon whether it is desired to have the single filament lamp.

plurality of lamps. By a single instru mentality it is thus possible to turn on a lamp or lamps either bright or dim, or-turn them off as desired.

The lamp of my invention may be used in an ordinary so-called Edison socket having a central disk terminal and an outer screw-threaded terminal without any change or any adapter as is necessary with most multiple filament lamps.

The advantages of the lamp are its sim plicity, reliability and adaptability.

What I claim .is:

1. An incandescent electric lighting apparatus, comprising a socket having three terminals, a three-wire conductor connected to said terminals, a switch in said socket adapted to control the circuit to one of sald terminals, and a removable bulb having a plurality of filaments of different resistances with fixed concentric terminals adapted to be connected to said socket terminals.

2. Incandescent electric lighting apparatus comprisinga socket having a threaded terminal and two yielding terminals and a removable bulb member having two fila ments, an exterior terminal for one filament, a central terminalfor the other filament, one of said two latter terminals being threaded, and an annular terminal common to both filaments, the two yielding socket terminals engaging the annular bulb termi nal and'the non-threaded bulb terminal re- 

